The present invention relates generally to optical networking, and more particularly, to a device for displaying the operating wavelength of wavelength tunable equipment in real time on the equipment.
In a traditional wavelength division multiplexing (WDM) system having transponders operating at a fixed wavelength, such wavelength is set during the manufacturing process. Within the WDM system, each transponder operates at a unique wavelength and, in terms of hardware and software, differs from other transponders operating at diverse wavelengths. For operational and maintenance purposes, the wavelength is usually printed or marked on the faceplate of each transponder. As wavelength tunable technologies are maturing, tunable transponders and other optical devices are starting to be deployed in WDM optical networks. In this regard, the wavelength of these transponders and other devices can be dynamically tuned as needed during operation. Within a WDM system, tunable transponders are physically the same, irrespective of the operating wavelength. Although each has the same hardware and software, the only difference between these transponders is that each is tuned to a unique wavelength during operation. The particular wavelength associated with each transponder can only be read from the craft interface terminal (CIT) and/or element management system (EMS), but cannot be readily identified directly from the equipment since all the transponders are structurally identical and look the same on the equipment. Consequently, operational personnel cannot ascertain the wavelength of each transponder by simply looking at the transponder, or without access to a CIT and/or EMS. For troubleshooting and other maintenance activities, it is a quite difficult and time-consuming task for operational personnel to identify a specific transponder among many such units. Moreover, there is a potential risk for traffic interruption if the personnel perform maintenance on the wrong transponder. On the other hand, it is undesirable to label (via printing or marking) the wavelength on each piece of equipment, particularly in the case of tunable WDM equipment, where the wavelength of a unit can be dynamically tuned during operation. It is not cost effective and a waste of resources to re-label the wavelength on such equipment every time the operating wavelength is changed to suit a particular application.